- add backwards compatibility for debug and debug_format. - deprecate debug_format, but not 'debug'
- add backwards compatibility for debug and debug_format.
- deprecate debug_format, but not 'debug'

tinglinux/logstash-kafka,opentable/logstash-kafka,joekiller/logstash-kafka,tinglinux/logstash-kafka,Aloomaio/logstash-kafka,joekiller/logstash-kafka,opentable/logstash-kafka,Aloomaio/logstash-kafka